Acid esters of acyl-phosphorous acids and method of making the same



United States ACID ESTERS OF ACYL-PHOSPHOROUS ACIDS AND METHOD OF MAKING THE SAME N Drawing. Application May 7, 1957 Serial No. 657,496

Claims priority, application Germany May 8, 1956 18 Claims. -(Cl. 260-461) This invention relates to acid esters of acyl-phosphorous acids and their salts and to a method of preparing the same from halides of monobasic or polybasic carboxylic acids and di-substituted phosphites.

It is known that the ethyl ester of acetyl-phosphorous acid or benZoyl-phosphorous acid may be obtained by a reaction between acetyl chloride or benzoyl chloride and triethyl phosphite. The neutral esters thus obtained decompose upon saponification either into the corresponding carboxylic acid and phosphorous acid or into the corresponding aldehyde and phosphoric acid. It is therefore not possible to produce acid esters of acyl-phosphorous acids or their salts by this method.

It is an object of the present invention to provide a process for the production of new and useful acid esters of acyl-phosphorous acids or their salts from readily accessible starting materials.

Other objects and advantages of our invention will become apparent as the description proceeds.

We have discovered that acid esters of acyl-phosphorous acids may be produced in a very simple fashion by reacting halides of monobasic or polybasic carboxylic acids with di-substituted phosphites at elevated temate peratures. When a monocarboxylic acid halide is used,

the reaction in accordance with the present invention probablyproceeds in accordance with the following general equation.

In this equation R and R represent identical or dilierent aliphatic or cycloaliphatic hydrocarbon radicals with preferably less than 8 carbon atoms, and R" represents an aliphatic, cycloaliphatic or aromatic hydrocarbon radical. The radicals R, R and R" may be straight-chain hydrocarbon radicals or also branched-chain hydrocarbon radicals. They may also be substituted, for example halogensubstituted. The radical R may 'in addition be interrupted by heteroatoms; that is, by oxygen, sulfur or nitrogen atoms. If the halide of a dibasic or polybasic carboxylic acid is used as the starting material for the process in accordance with the invention, dibasic or polybasic acid esters are formed in analogous fashion, for example, in accordance with the following equation:

Accordingly, the halides, preferably the chlorides or bromides, of aliphatic, cycloaliphatic or aromatic monocarboxylic, dicarboxylic or polycarboxylic acids, the hydrocarbon radicals of which carry various substit-uents or t 2 are also interrupted by heteroatoms or hetero atom groups, may be used as starting materials for the process according to the present invention; such acids are, for example, acetic acid, butyric acid, isobutyric acid, lauric acid and higher fatty acids, mono-, di-jand trichloroacetic acid, as well as other halogenated carboxylic acids, ether-carboxylic acids, thioether-carboxylic acids, aminocarboxylic acids, cyclohexane-carboxylic acid, benzoic acid and other substituted or unsubstituted. aromatic carboxylic acids, as Well as diand poly-carboxylic acids, such as adipic acid, sebacic acid, tricarballylic acid, phthalic acid, tetrachlorophthalic acid, terephthalic acid, trlmesic acid, and the like.

Di substituted phosphites which may be reacted with the carboxylic acid halides in accordance with the invention are, for example, diethyl phosphite, di-isopropyl phosphite, dibutyl phosphite, dioctyl phosphite, di-(Z- chloroethyD-phosphite, and the like.

The two reaction components are preferably used in quantitative ratios such that about one mol of di-substituted phosphite is present for each CO-Hal group. The presence of an excess of one or the other reaction components, however, is not detrimental.

The reaction takes place at elevated temperatures, preferably between 50 and C. In some cases, especially when a particularly reactive carboxylic acid halide is used, it is advantageous to carry out the reaction in the presence of an inert organic solvent or diluent, such as carbon tetrachlorodie or benzene.

As indicated by the above equations, the reaction proceeds with the formation of an aliphatic or cycloaliphatic halide. If a low-molecular aliphatic alcohol is used for the production of the disubstituted phosphite, this hydrocarbon halide continuously distills out of the reaction mixture during the reaction. If a high-molecular aliphatic or cycloaliphatic alcohol is used to produce disubstituted phosphite, the hydrocarbon halide may be distilled off vacuo during or after the reaction.

The acid esters of acyl-phosphorous acids obtained by reaction in accordance with the invention are useful as capillary-active agents for various purposes, for example as cleaning agents or washing agents. The acid ester of acy-l-phosphorous acid as described above may be transformed into their salts, for example their alkali metal salts in a very simple fashion. These salts are likewise useful as capillary-active agents and may be used alone or with usual substances, for example phosphates, alka line carbonates and silicates as washing agents, cleaning agents or as textile-finishing agents.

The acid esters may also be transformed into other acid esters by ester-radical exchange or into neutral esters by heating them, preferably with high-molecular alcohols and, necessary, in the presence of suitable esterification catalysts.

The polybasic esters of acyl-phosphorous acids produced from the halides of diand polycarboxylic acids in accordance with the present invention may also be reacted with polyvalent alcohols to form acid or also neutral polyesters of varying molecular size. a

The following examples will further illustrate the present invention and enable others skilled in the art to understand the invention more completely. However, it is understood that our invention is not limited to the embodiments illustrated in these examples.

Example vI 29.2 gm. of the residue were stirred with a solution of to s. s daei asa a 7 3 4 gm. sodium hydroxide in 1.4 liters water. foaming, turbid solution, similar to a soap solution, was formed. From this solution the pure sodium salt of the monoethyl ester of lauroyl phosphorous acid was obtained in a solid form by salt-ing out with sodium chloride.

Example II A mixture of 61 gm. adipic acid dichloride and 92 gm. diethyl-phosphite was stirred for 8 hours at 90-95 C.; 40 gm. ethyl chloride distilled ofi during that time. The reaction product, the di-monoethyl ester of adipoyl phosphorous acid, was a colorless, viscous: liquid which dissolved in water to form a clear solution having an acid reaction. Example III A mixture of 55.2 gm. diethyl-phosphite and 56.2 gm. benzoyl chloride was heated for 20 hours at a temperature between 85 and 95 C., accompanied by stirring; 25 gm. ethyl chloride distilled oil during that time. The reaction product, the monoethyl ester of benzoyl phosphorus acid, was a viscous, colorless, clear liquid which readily dissolved in dilute sodium hydroxide upon being shaken therewith.

Example IV A mixture of 19 gm. capric acid chloride and 14.5 gm. diethyl-phosphite was stirred for 8 hours at a temperature between 85 and 95 C.; 6 gm. ethyl chloride distilled'off during that time. The residue, the monoethyl ester of caproyl phosphorous acid, was a clear, colorless, moderately viscous oil which was readily soluble in dilute sodium hydroxide.

Example V A mixture of 81, gm. 2-ethylhexanoic acid chloride and 69 gm. diethyl phosphite was stirred for about6 hours at a temperature between 90 and 95 C. until no more ethyl chloride distilled oflf. 102 gm. of the moderately viscous residue formed thereby were heated in admixture with 112 gm. Z-ethylhexanol at 100 C. while passing a slow stream of nitrogen therethrough until a reduction in weight of 17 gm. occurred. Thereafter, the excess Z-ethylhexanol was distilled oil at a vacuum of 2.5 mm. Hg. The residue had an acid number of 142 and a saponification value of 273 (calculated values for C7H15cO-PO(OH)OC3H17Z143 and 286, respectively). The acid ester dissolved in dilute sodium hydroxide. The solution foamed and exhibited excellent wetting properties.

Example VI A mixture of 109.3 gm. lauroyl chloride and 97 gm. dibutyl phosphite was heated to 95 C. while passing nitrogen therethrough; the butyl chloride formed thereby was trapped in a condenser. After about 20 hours no more butyl chloride split E. The reduction in weight of the reaction mixture was 43.5 gm. The residue was a viscous, almost colorless oil. The phosphorus and carbon content of the reaction product corresponded to the formula The chlorine content was smaller than 0.1%. The acid number was 182l86 (calculated 175) and the saponification value was 355-363 (calculated 350).

Example VII For the cleaning of foodstuff containers, preferably of metal there is excellently suited a product of the following composition: V V 30% by weight trisodium phosphate (12 H 0).

55% by weight sodium silicate solution 40 B. by Weight monoethyl ester of lauroyl phosphoric acid obtained as described in Example I, paragraph 1 Water, balance.

A strongly This composition was used after dilution in water (about 10 grams per liter). The solution has good cleaning properties.

Example VIII 50 parts trisodium phosphate 20 parts sodium tripolyphosphate 10 parts sodium sulfate 20 parts acid ester, obtained as described in Example I, paragraph 1 are mixed. The product obtained in this manner after dissolving in water (about 10 grams per liter) is an excellent dishwashing composition.

Example IX A cleaning agent of similar quality is obtained, if in the above (Example VIII) indicated combination, the acid ester is replaced by 20 parts of the sodium salt of the acid ester, which is described inExample I, paragraph 2.

Example X An excellent metal cleaning agent is obtained by preparing a 2% aqueous solution of a mixture of the fol lowing composition:

25 parts di-monoethyl ester of adipoyl phosphorous acid,

obtained as described in Example II 50 parts sodium sulfate 24 parts sodium pyrophosphate (Na H P O 1 part 2-mercaptobenzthiazol.

While we have illustrated a few specific embodiments of the present invention, it will be readily apparent to those skilled in the art that the invention is not limited to these embodiments and that various changesand modifications may be made without departing from the spirit of the invention or the'scope of the appended claims.

We claim:

1. The process of producing acid esters of acyl-phosphorous acid, which comprises heating a mixture of an organic carboxylic acid halide and a di-lower alkyl phosphite in a ratio of 1 mol di-lower alkyl phosphite per -CO-halide group in the carboxylic acid halide to a temperature between 50 and 150 C., and removing the lower alkyl halide from the reaction mixture.

2. The process of producing the monoethyl ester of lauroyl phosphorous acid, which comprises heating a mixture of equimolar amounts of diethyl-phosphite and lauroyl chloride to a temperature between and 95 C., and removing the ethyl chloride formed thereby from the reaction mixture.

3. The process of producing the di-monoethyl-ester of adipoyl phosphorous acid, which comprises heating a mixture of 1 mol adipic acid dichloride and 2 mols diethyl- I phosphite to a temperature between and C., and

removing the ethyl chloride formed thereby from the reaction mixture.

4. The process of producing the monoethyl ester of benzoyl phosphorous acid, which comprises heating a mixture of equimolar amounts of diethyl-phosphite and benzoyl chloride to a temperature between 85 and 95" C., and removing the ethyl chloride formed thereby from the reaction mixture.

5. The process of producing the monoethyl ester of caproyl phosphorous acid, which comprises heating a mixture of equimolar amounts of capn'c acid chloride and diethyl-phosphite to a temperature between 85 and 95 C., and removing the ethyl chloride formed thereby from the reaction mixture.

6. The process of producing the monoethyl ester of Z-ethylhexanoyl phosphorous acid, which comprises heating a mixture of equimolar amounts of Z-ethylhexanoic acid chloride and diethyl-phosphite to a temperature between 90 and 95 C., and removing the ethyl chloride formed thereby from the reaction mixture.

and

wherein R is an alkyl radical, and R" is selected from the group consisting of monoand di-valent saturated aliphatic and aromatic hydrocarbon radicals containing 1 to 7 carbon atoms and the radicals of saturated monovalent higher fatty acids, and the alkali metal salts thereof.

9. The monoethyl ester of laurc-yl phosphorous acid.

1 0. The di-monoethyl ester of adipoyl phosphorous acid.

11. The monoethyl ester of benzoyl phosphorous acid.

12. The monoethyl ester of caproyl phosphorous acid.

13. The monoethyl ester of Z-ethylhexanoyl phosphorous acid.

14. The monobutyl ester of lauroyl phosphorous acid.

15. Acid esters of acyl-phosphorous acids having a structural formula selected from the group consisting of and A OR

16. The process of producing acid esters of acyl-phosphorous acid havinga structural formula selected from the group consisting of wherein R is selected from the group consisting of lower alkyl radicals with less than eight carbon atoms, and R" is selected from the group consisting of monoand divalent aliphatic, cycloaliphatic and aromatic radicals containing from 1 to 18 carbon atoms, which comprises heating a mixture of a carboxylic acid halide having a structural formula selected from the group consisting of R"CO-Hal and c 0 Hal wherein R has the meaning above indicated and Hal is a halogen atom, and a di-substituted phosphite having the structural formula RO\ /O wherein R has the meaning above indicated and R is selected from the group consisting of lower alkyl radicals with less than 8 carbon atoms, in a ratio of 1 mol di-substituted phosphite per-CO-halide group in the carboxylic acid halide to a temperature between 50 and C., and

' removing the lower alkyl halide formed by the reaction from the reaction mixture.

17. The mono-Z-ethylhexyl ester of 2-ethylhexanoyl phosphorous acid.

18. The sodium salt of the mono-ethyl ester of lauroyl phosphorous acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,491,920 Emsberger Dec. 20, 1949 2,629,731 Harman Feb. 24, 1953 2,719,167 Schmidt Sept. 27, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION I Patent Noo 2 9%,4138 August 18, 195(5 Bruno Blaser et a1 It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2,, line "tetraciklorodie" read tetrachloride column 6;, lines 21 22, for "aliphatic cyoioaliphatic and aromatic containing from 1 to 18 carbon atoms" saturated aliphatic and hydrocarbon radicals containing 1 to '7 carbon.

the of setur-ted monovalent fatty n Signed. this 29th dug; of Mercia 19660 (SE-KL) Attest:

KARL ROBERT C. WATSON Attesting Oificer Y Y Commissioner of Patents 

8. ACID ESTERS OF ACYL-PHOSPHOROUS ACIDS HAVING A STRUCTURAL FORMULA SELECTED FROM THE GROUP CONSISTING OF
 16. THE PROCESS OF PRODUCING ACID ESTERS OF ACYL-PHOSPHOROUS ACID HAVING A STRUCTURAL FORMULA SELECTED FROM THE GROUP CONSISTING OF 